Clamp(value, min, max) returns min when min > max instead of throwing ArgumentException

[matt-edmondson]

What's wrong

The instance Clamp<TNumber> (PreciseNumber/PreciseNumber.cs:575-582) never checks that min <= max. The static INumber<T>.Clamp at ~line 1713 calls it, so the check is missing there too:

PreciseNumber clampedToMax = this > sigMax ? sigMax : this;
return this < sigMin ? sigMin : clampedToMax;

Reproduced on net10.0:

• PreciseNumber.Clamp(2, 3, 1) returns 3
• PreciseNumber.Clamp(5, 3, 1) returns 3

Math.Clamp, decimal.Clamp, int.Clamp and the default INumber<T>.Clamp all throw ArgumentException when min > max.

Why it matters

An inverted range is almost always a caller bug, such as swapped arguments or a computed bound. The BCL reports it loudly. PreciseNumber instead returns a value that satisfies neither bound from the caller's point of view. Generic code written against INumber<T> behaves differently depending on whether T is decimal or PreciseNumber. The existing tests (PreciseNumberTests.cs:68-93, 384-393) only cover valid ranges.

Suggested fix

After converting the bounds, add if (sigMin > sigMax) throw new ArgumentException(...). Mirror the BCL message: "'min' cannot be greater than 'max'".

Acceptance criteria

• PreciseNumber.Clamp(2, 3, 1) throws ArgumentException, through both the static and the instance overloads.
• A test covers the inverted range.